| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 461 | Isolde | Celtic | The fair. | F | |
| 462 | Jarvis | Celtic | Variant of Gervase: Servant spear. This name is derived from combining an Old Gcrman name meaning spear, and the Celtic word for servant. Famous bearer: martyr St Gervase who died in Milan. | M | |
| 463 | Jennifer | Celtic | White wave. | F | |
| 464 | Jenny | Celtic | White wave. | F | |
| 465 | Jennyfer | Celtic | White wave. | F | |
| 466 | Jennyver | Celtic | White wave. | F | |
| 467 | Joyce | Celtic | Feminine of Jodoc. | F | |
| 468 | Kane | Celtic | Warrior. Intelligent. Popular as a first name in Australia. | M | |
| 469 | Karney | Celtic | Fighter. | M | |
| 470 | Kayne | Celtic | Intelligent. | M | |
| 471 | Keaghan | Celtic | Son of Egan. | M | |
| 472 | Keane | Celtic | Tall and handsome. | M | |
| 473 | Kearney | Celtic | Fighter. | M | |
| 474 | Keary | Celtic | Dark. | M | |
| 475 | Keegan | Celtic | Son of Egan. | M | |
| 476 | Keelia | Celtic | Slender or comely. | F | |
| 477 | Keelin | Celtic | Slender or comely. | F | |
| 478 | Keely | Celtic | Slender or comely. | F | |
| 479 | Keene | Celtic | Tall and handsome. | M | |
| 480 | Kegan | Celtic | Son of Egan. | M | |